Valve Repair in Aortic Insufficiency: A State-of-the-art Review

Abstract

Aortic valve insufficiency (AI) describes the pathology of blood leaking through the aortic valve to the left ventricle during diastole and is classified as mild, moderate or severe according to the volume of regurgitating blood. Intervention is required in severe AI when the patient is symptomatic or when the left ventricular function is impaired. Aortic valve replacement has been considered the gold standard for decades for these patients, but several repair techniques have recently emerged that offer exceptional stability and long-term outcomes. The appropriate method of repair is selected based on the mechanism of AI and each patient's anatomic variations. This review aims to describe different pathologies of AI based on its anatomy, along with the different surgical techniques of aortic repair and their reported results.

Keywords: Aortic insufficiency; aortic annuloplasty; aortic insufficiency classification; aortic valve repair; valve-sparing aortic root replacement; ventricular diastole.

Fig. (1)

Schematic representation of the aortic valve modified from Matsushima et al. [19]. The aortic valve, which is cylindrical in shape, has three leaflets with a 3D crown-like configuration. Each leaflet comprises two free margins, which are shared with the neighboring leaflets. The VAJ corresponds to the imaginary line that connects the lower third of the aortic cusps and goes through the interleaflet trigones’ bases. The lowest point of each semilunar insertion line is termed the leaflet nadir, with the virtual circumferential line connecting these nadirs being the VBR. Abbreviations: STJ: sinotubular junction; VAJ: ventriculoaortic junction; VBR: virtual basal ring.

Fig. (2)

Schematic representation of the anatomy of the aortic valve modified from Netter’s “Atlas of human anatomy”. The figure demonstrates an opened aortic valve showing the right, left and the non-coronary leaflets and their related detailed anatomy. Each leaflet has a semilunar line travelling from the aortic annulus to the STJ, the body of the leaflet, and two free margins with a thickened, central, and circular fibrous nodule (Body of Arantius). Because of the semilunar insertion attachment of the leaflets, three interleaflet triangles are formed as extensions of the left ventricular outflow tract and are found below the commissure in between the bases of two adjacent leaflets. The commissures, the leaflets’ nadir, and the lower third of the aortic cusps attain the level of the STJ, VBR, and VAJ, respectively. Abbreviatons: NC: non-coronary sinus; RC: right coronary sinus; LC: left coronary sinus; STJ: sinotubular junction; VAJ: ventriculoaortic junction; VBR: virtual basal ring.

Fig. (3)

Schematic representation of the effective and geometric height modified from De Kerchove et al. [20]. The effective height is defined as the orthogonal length between the aortic annulus and the middle of the free margin. The geometric height is the distance between the nadir and the middle of the free margin of the leaflet. Abbreviations: eH: effective height; gH: geometrical height; STJ: sinotubular junction; VBR: virtual basal ring.

Fig. (4)

Classification of aortic insufficiency (AI) and suggested surgical approaches. Type I AI has normal leaflet motion and is associated with functional aortic annulus dilation or cusp perforation, type II is associated with cusp prolapse, and type III with cusp restricted motion. A standardized approach addresses all different pathologies identified: type Ia AI repair involves Asc graft and STJ remodeling; type Ib AI repair involves VSSR procedures; type Ic AI repair involves SCA; type Id AI repair requires the use of a pericardial patch; type II AI repair approach is based on leaflets’ condition; type III AI repair involves shaving excess fibrous tissue and removal of calcium deposits with/without patch). Care should be taken that the final effective height of the aortic valve cusps is 8-10mm at the end of the repair. Abbreviations: STJ: sinotubular junction; Asc: ascending aorta; SCA: subcommissural annuloplasty; VAJ: ventriculoaortic junction; VSRR: valve-sparing aortic root replacement. Modified from Prodromo et al. [22].